The use of a blunt cannula for penetrating access devices having a preslit septum, without tearing or displacing the septum is known. The use of such blunt cannula is not designed for and is not capable of penetrating solid unslit rubber stoppers or septums of drug vials or other medicine containers. Pointed cannulas, needles, and drug vial spikes are well known instruments that can be used to pierce and penetrate such solid unslit rubber stoppers or septums of drug vials or other medicine containers.
In the practice of combining and dispensing medicine it is sometimes necessary to access different containers that comprise both solid and preslit septums. For example, it may be necessary to access a first drug container containing a liquid medicine to remove a quantity of the medicine via a syringe and the like, and then inject the quantity of medicine into a fluid path accessed by an injection site or the like having a preslit septum. The practice of accessing a preslit septum using a sharp-tipped device, such as a sharpened cannula, needle or drug spike, can cause the septum to be physically damaged in the form of coring or laceration, which can result in subsequent leakage.
The use of sharp-tipped instruments is also not desired for uses other than those specifically requiring use of the same, e.g., to access a solid septum, due to the potential hazards associated with infectious agents. Personnel using such sharped-tipped instruments are trained to do so with great care. However, instances are known to occur where a person using such a sharp-tipped instrument punctures themself while attempting to perform an operation that does not require the use of such sharp-tipped instrument, e.g., when accessing a preslit septum. It may be that such past accidents, and future accidents, could be avoided by selecting the proper instrument for the particular operation. The choice of selecting the proper instrument for a particular operation may not always be an attractive or an available option, given the time window within which the operation must be performed, or given the ready availability of instruments. For example, an emergency situation may call for the rapid mixing and/or dispensing of medicine, or the unavailability of instruments may call for improvision.
In an effort to overcome the difficulties and potential hazards relating to the use of the proper instrument for accessing both preslit and unslit septums, devices have been constructed for insertion within a fluid-flow passage of a blunt cannula for providing such cannula with a pointed tip. Referring to FIG. 1, U.S. Pat. No. 5,411,499 discloses such a device 10 generally comprising a piercing member 12 having a shaft 16 that is disposed within a fluid-flow channel 18 of a blunt cannula 20. The blunt cannula 20 has a Luer flange 22 at a first end 24, for connecting to an engaging structure (not shown). The piercing member 12 comprises a pointed tip 26 at a distal end of the shaft 16 that projects from a tip 28 of the cannula fluid-flow channel 18 having a tapered outside surface, to permit the blunt cannula to be used to access a solid septum. However, the construction of the device does not permit accessing more than one container that comprises a solid septum, as the piercing member 12 is designed to be removed from the cannula 20, and be retained within the solid septum, when the cannula is withdrawn from the solid septum.
It is, therefore, desired that a device be constructed that facilitates the use of a blunt cannula for accessing both solid and preslit septums. It is desired that the device be constructed so that it will enable the blunt cannula to be used for accessing more than one container comprising a solid septum without the need to replace assembly components or use additional assemblies. To promote application flexibility, it is also desired that such device be constructed to facilitate use with existing blunt cannula designs. It is further desired that the device be constructed in a manner that promotes ease of use without additional equipment, tools or training.